The F-109 designation was initially assigned to what was to become the
McDonnell F-101B. After the two-place version of the "Voodoo" was re-designated,
the USAF reassigned the designation to Bell Aircraft Corporation Model D-188A.
The project, sponsored by both the USAF and US Navy, called for a vertical
takeoff and landing (VTOL) interceptor capable of speed in excess of Mach 2.

Although the aircraft never got beyond the mock-up stage, it had some
unusual design features. The aircraft was to have
eight J85 turbojet engines; a
pair of engines was mounted on each wingtip in a rotating nacelle, the other
four engines were mounted in the fuselage, two horizontal in the aft section and
two vertically in the forward fuselage to provide downward thrust for hover and
low speed flight. The wingtip nacelles were designed to rotate through a 100
degree arc; horizontal to 10 degrees past vertical, allowing the aircraft to fly
a backwards hover.

The J85 augmented turbojet is a powerplant for
high performance trainers and tactical aircraft. With more than 75 million
flight hours experience on military and commercial models, the J85 offers the
highest thrust-to-weight ratio of any production engine in its class in the free
world.

J85 engines first entered service in 1960. More than 6,000 engines flying in a
number of applications remain in active service in 35 countries. Current plans
for the U.S. Air Force (USAF) call for J85-powered aircraft to be in service
through 2040.

Although temporarily assigned to several projects, it now appears that the
designation F-109 was never actually used by any aircraft.

In 1955, the McDonnell Corporation proposed that the designation F-109 be
assigned to the two-seat all-weather interceptor variant of the Voodoo. The Air
Force turned down this proposal, and the aircraft was assigned the designation
F-101B instead.

Throughout the 1950s there were published reports that the F-109 designation
had been assigned to a vertical-takeoff aircraft designed by the Ryan
Aeronautical Company. However, this aircraft was actually designated
X-13 (a
designation in the X-for-experimental series). The X-13 was strictly
experimental and was never intended as an operational fighter aircraft, and it
never actually bore the F-109 designation.

Many references that I have read state that the F-109 designation was
assigned to the
Bell D-188A, a late 1950s private venture proposal by the Bell
Aircraft Corporation for a Mach 2+ V/STOL fighter. This proposal called for a
high-winged aircraft powered by eight General Electric J85-GE-5 turbojets. Two
of these engines were mounted horizontally in the rear fuselage and were fed by
cheek-type air intakes mounted on the sides of the rear fuselage. Two other J85
engines were mounted vertically in the fuselage behind the pilot's cockpit. They
provided lift during vertical takeoff and landing, but were shut down for
ordinary horizontal flight. The other four engines were mounted in two pairs in
movable pods at the wingtips. The pods were rotated into a vertical position for
vertical takeoff and landing, then were rotated horizontally for level flight.

The project had gotten as far as the mockup stage when, in February 1958, the
Bell Aircraft Corporation requested that the USAF assign the designation XF-109
to the D-188A project. The Air Force had no interest in the proposal and turned
down the request. Consequently, the D-188A never, in fact, received a USAF
designation, although the USAF serial numbers 59-2109 and 60-2715 have been
associated with this project. In the event, the D-188A never did find favor with
the military, although the general concept was later taken up by West Germany in
the E.W.R-Sud VJ 101C.

Sources:

United States Military Aircraft Since 1909. Gordon Swanborough and Peter
M. Bowers, Smithsonian, 1989.

Fighters of the Unites States Air Force, Robert F. Dorr and David Donald,
Temple Press Aerospace, 1990.

The American Fighter, Enzo Angelucci and Peter Bowers, Orion, 1987.

BY JOE BAUGER

The XF-109 Photo Gallery

Click on Picture to enlarge

"In 1953 Bell developed the Model 65 ATV, a VTOL research aircraft with a
pair of rotating turbojets mounted to each side of the airframe. These could be
moved enough to allow the plane to get vertically airborne. Though it ended
just two years later, the program gave Bell experience with VTOL aircraft. This
led to project D.188A, a joint USAF/USN program for the XF-109/XF3L. It was
designed to be in the same general performance class as the F-104, a Mach 2
fighter of much lighter weight. To reach this goal, the XF-109 was to be powered
by eight engines. Two in the aft fuselage, two vertically behind the cockpit and
the other four in two wingtip pods that could swivel to provide either vertical
or horizontal thrust. In 1960, the Navy pulled out of the program as it was
tired of the constant delay in engine development. A year later, the USAF also
lost interest and pulled the plug after only a mockup had been built. Once
again, a promising aircraft was still-borne thanks to a lagging engine
development program! That engine, by the way, was the General Electric J-85,
which went on to provide sterling service in the T-38/F-5 program and in many
cruise missiles!